Defrosting system



Oct. 3, 1950 w, MQRRISQN 2,524,465

DEFROSTING SYSTEM Filed April 26, 1946 2 Sheets-Sheet 2 Patented Oct. 3, 1950 UNITED STATES PATENT oFFicE DEFROSTING SYSTEM Willard L. Morrison, Lake Forest, Ill. Application April 26, 1946, Serial No. 665,182

(Cl. (i2-103i 4 Claims. l

My invention relates to an improvement in refrigeration and has for one purpose to defrost a cooling unit without raising the `temperature within the refrigerator.

Another purpose is to provide a plurality of evaporator units which may be selectively put into heat abstracting relation with the interior of a refrigerator.

Another purpose is to provide a secondary evaporator for effective use during the de-icing of a primary evaporator.

Another purpose is to provide two evaporators, of different heat abstracting capacity, with means for placing them selectively in heat abstracting relationship with a storage zone.

Another purpose is to provide a primary evaporator, and a secondary evaporator, and to provide means for putting the primary evaporator in heat abstracting relationship with a secondary evaporator, when the primary evaporator is not cycling.

Another purpose is to provide an arrangement of evaporators in which one evaporator is employed to dehydrate or abstract moisture from the other.

Other purposes will appear from time to time in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in the accompanying drawings in which:

Fig. 1 is a front exterior view;

Fig. 2 is a vertical section through Fig. l;

Fig. 3 is a section taken on the line 3--3 of Fig. 2; and

Fig. 4 is a diagrammatic drawing of the refrigeration circuit.

Referring to the drawings,` I represents the doors of the refrigerator, 2 represents the outside wall of the refrigerator, 3 the inside wall with insulation d between them, 5 represents the primary cold plate or evaporator, and 6 the shelves to carry food. n

In Fig. 2 the second cold plate l is shown enclosed within the insulated area 8 and in Fig. 3 the cold plate` 'l is shown outside the insulated area 9 represents the insulated portion that can be transposed from groove IIJ below the second cold plate or evaporator 'I vto groove I I above the cold plate l. f

There are numerous ways in which this transposition can be accomplished but for the purposes of this invention I use a drawer-like device I2 which has insulation 9 securely attached to it. The drawer can be pulled out by means of handles i3, and its position reversed, so that the insulation is above the cold plate, and the drawer can then be pushed back again. The drain pan I4 is attached to the insulation 9 and when the second cold element I is outside the insulated area 8 as in Fig. 3, and has been turned olf, the frost that has accumulated on the cold plate will melt and drop down on this drain pan vand be carried off through faucet I5.

Fig. 4 is a diagrammatic drawing of the refrigeration circuit in which I6 represents the compressor driven by motor Il. The refrigerant at high pressure leaves the compressor I6 at exit I 8, travels through passage I9 and enters condenser ZI at entrance 20. The liquiiied refrigerant passes from condenser 2l through opening 22, and travels through the passage 23 to the 2-way switch 25. The adjustment shown in Fig. 4 shows the refrigerant going through passage Ztl and thence to 26 and working restrictor 3d to cold plate 5 from where it exits at opening 2'@ to empty into suction manifold 3l at 28 and by means of passage 3| it returns at low pressure to compressor I6 at 32.

A temperature bulb 36 placed inside area 8 will maintain a constant temperature within that area by its connection with switch 33 which causes the motor to run the compressor whenever the temperature in area t rises above a certain point. Thus because cold element l is considerably smaller than cold element 5 the plate 'l will of necessity become colder than plate 5 in order to maintain a constant temperature in area 8, and by virtue of being colder will attract to it the ice formations on plate 5.

When defrosting the plates 5, the switch 25 is adjusted so that the refrigerant is shut oi from passage 26 and plate 5 and is routed through pas` sage 29 through defrosting restrictor 35, to plate 1 from where it exits at opening 30 into common manifold 3l, and thence back to the compressor I 6 as before described.

It will be realized that whereas I have shown a practical and operative device, nevertheless many changes may be made in size, shape, number and disposition of parts without departing from the spirit of my invention. I, therefore, wish my description and drawings to be taken as in a broad sense, illustrative or diagrammatic.

The use and operation of my invention are as follows:

To defrost the cold element in existing refrigerators involves the necessity of warming the refrigerator for a period long enough for the frost to melt and drain olf. This is a great inconvenience and involves the danger of food spoilage during the period when there is no refrigeration. .My invention eliminates that danger by putting a second and colder element into operation within the insulated area during the period when the first refrigeration element is turned oif, thus the ice formation on the rst refrigeration element will transfer by sublimation to the second refrigeration element. This position is illustrated in Fig. 2. Drawer I2 is in the position that places insulation 9 above the cold plate 1 thus enclosing cold plate 1 in the insulated area 8. Switch 25 is adjusted so that the refrigerant is shut oiI from plates 5 and flows instead through 29 and 35 to plate 1. The temperature gauge 36 will regulate the compressor in order to maintain a constant temperature in area 8 and in doing this will automatically cause the cold plate 1 to be colder than cold plate 5 because plate 1 is smaller than plate 5. After plates 5 have been defrosted, 2-way switch 25 is adjusted so as to shut olf the refrigerant from plate 1 and reroute it to plate 5, the drawer like device is reversed so that the insulation 9 is between plate 1 and area 8 as shown in Fig. 3. Drain pan i4 which is attached to insulation 9 and occupies the space between the insulation and the cold plate, collects the moisture that melts off oi plate 1 when no refrigerant travels through it. Thus plate 1 is defrosted and drains off through faucet I5 into some handy receptacle.

-In considering the system above described, it should be understood that it has a wide variety of applications. One application is, as above pointed out, to permit defrosting of a domestic refrigerator without undue or damaging heating loss, and without interruption of the storage efiiciency of the unit. My system is also adaptable for use in situations where an alternative temperature or successive variations of temperature, are desired in a given storage space. For example, I can convert an above freezing storage cabinet into a below-freezing storage cabinet by cutting in one evaporator and cutting out another. Another possible application is to industrial systems where a series of successive or recurrent temperatures of different ranges is desired in the same space.

I claim:

1. In a refrigerator, an insulating housing, a portion of the wall of the housing being uninsulated, a working cold heat exchange element associated with the insulated walls of the housing, an auxiliary cold heat exchange element adjacent the uninsulated wall of the housing, means for selectively circulating refrigerant through one or the other of said heat exchange elements, and a movable insulating Ipartition, means for supporting it selectively between the auxiliary cold element and the uninsulated housing wall or between the auxiliary cold element and the remainder of the refrigerator, means associated with the partition operative when the partition is between the auxiliary cold element and the body of the refrigerator for disposing of water of condensation from the auxiliary element.

2. The method of defrosting a refrigerator wherein there are a plurality of cold heat ex- Number change elements, one of larger size than the other which consists in selectively circulating refrigerant through oneor the other of said elements, meanwhile maintaining temperature constant in the refrigerator by controlling the circulation of refrigerant to give a lower temperature in the auxiliary heat exchange element than in the working heat exchange element, defrosting the refrigerator by exposing both elements to the interior of the refrigerator, circulating refrigerant only through the auxiliary element until the moisture deposited on the primary element has by sublimation been deposited on the secondary element, then separating the secondary element from the refrigerator ceasing the passing of refrigerant therethrough and causing refrigerant to circulate through the primary element.

3. In a refrigerator, an insulating housing, a plurality of heat exchange elements contained therein, a refrigerant circulation system with which said heat exchange elements are connected, means for selectively circulating the refrigerant through one or the other of said heat exchange elements, the heat exchange elements being so related that the temperature of one of them is much lower than the temperature of the other, whereby when both heat exchange elements are exaposed to the atmosphere in the housing, frost previously deposited on the warmer of the two elements is by sublimation and vapor pressure transferred to the colder of the two elements and means for thereafter insulating such colder element from the atmosphere in the refrigerator to permit the deposited frost to melt therefrom, and means for discharging the resulting moisture outside of the refrigerator.

4. The method of operating a refrigerator which consists in extracting heat from the interior thereof at a. relatively high temperature zone until the moisture in the refrigerator has been concentrated as a frozen mass in such zone, then while continuing the extraction of the heat from the refrigerator, extracting heat at a. higher rate and lower temperature in a second zone until the frozen moisture deposited in the higher temperature zone has been by sublimation transferred to the lower temperature zone, then while continuing the extraction of heat from the refrigerator, melting the frozen mass and discharging it from the lower temperature zone and from the refrigerator.

WILLARD L. MORRISON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date Belt Jan. 10, 1933 Phillips Feb. 20, 1934 Kalischer Oct. 25, 1938 Hovey June 6, 1939 Montgomery Dec. 24, 1940 Starr Feb. 2'7, 1945 Di Zoppola Dec. 30, 1947 

